This invention relates to electrical power generators for power generation plants, and specifically to suppression of noise generated by power generators and emitted by ventilation ducts.
Electrical power generators in power generation plants and other industrial facilities are noisy industrial machines. The generator noise is typically suppressed by sound insulation and baffles mounted to ventilation ducts associated with the generator. The ventilation ducts direct cooling air to and from the generator.
Baffles and insulation in a ventilation duct restrict the flow of the cooling air through the baffles and the generator. Specifically, the baffles and insulation cause a pressure drop in the cooling air flowing through the ducts. This pressure drop can result in a reduction of cooling air passing through and cooling the generator. Moreover, baffles and insulation are most effective at suppressing high frequency noise, such as noise at frequencies above 500 Hertz (Hz), than they are at suppressing low frequency noise.
An approach to reduce low frequency noises is to adjust the design of the rotor in the generator to reduce the amount of noise produced by the generator. However, adjusting the design of the rotor typically requires an expensive redesign and development of the rotor and other moving components in the generator.
In the above described difficulties in suppressing low frequency noise, there is a long-felt need for sound suppression devices for electrical power generators that do not restrict the flow of cooling air and are effective at suppressing noise from the generator, particularly low frequency noise. This need is greatest with respect to noise from large electrical power generators in power generation plants for power utilities and in industrial plants, such as large manufacturing facilities.